Levesque M A, D'Costa M, Diamandis E P
Department of Pathology, Mount Sinai Hospital, Toronto, Canada.
Br J Cancer. 1996 Nov;74(9):1434-40. doi: 10.1038/bjc.1996.561.
p53 protein, which accumulates intracellularly in over half of all human tumours, has also been reported to be present in the sera of patients with various malignancies, including lung cancer. Using a quantitative immunoassay, we measured p53 protein concentrations in 216 sera from 114 lung cancer patients of whom 75 provided matched lung tumour tissues, which were also assayed for p53 protein. p53 protein levels above the detection limit of 0.04 ng ml-1 were detected in only two sera from lung cancer patients (0.14 ng ml-1 and 0.27 ng ml-1), but not in any of 13 sera from non-malignant lung disease patients or in 100 sera from normal non-diseased individuals. The presence of these apparent traces of serum p53 protein concentrations could not be related either to the p53 protein expression status of the primary lung tumours or to the tumour stage, grade or histological type. By pretreating these two sera with anti-p53 antibody linked to solid phase, and by the addition of mouse serum to neutralise possible heterophilic antibodies, the signals arising from these sera were shown to be non-specific and possibly caused by heterophilic antibodies. We conclude that our data do not support previous reports of p53 protein in the sera of lung cancer patients. Since immunoassays are subject to numerous sources of interference in serum, including heterophilic antibodies, we suggest that the results of p53 protein analysis of serum specimens should be interpreted with caution.
p53蛋白在超过半数的人类肿瘤细胞内积聚，也有报道称其存在于包括肺癌在内的各种恶性肿瘤患者的血清中。我们采用定量免疫分析法，检测了114例肺癌患者的216份血清中的p53蛋白浓度，其中75例患者提供了配对的肺肿瘤组织，也对其进行了p53蛋白检测。肺癌患者的血清中仅有两份检测到p53蛋白水平高于0.04 ng/ml的检测限（分别为0.14 ng/ml和0.27 ng/ml），而13例非恶性肺病患者的血清以及100例正常非患病个体的血清中均未检测到。血清中这些明显微量的p53蛋白浓度与原发性肺肿瘤的p53蛋白表达状态、肿瘤分期、分级或组织学类型均无关联。通过用与固相连接的抗p53抗体预处理这两份血清，并加入小鼠血清以中和可能存在的嗜异性抗体，结果表明这些血清产生的信号是非特异性的，可能是由嗜异性抗体引起的。我们得出结论，我们的数据不支持先前关于肺癌患者血清中存在p53蛋白的报道。由于免疫分析在血清中会受到多种干扰因素的影响，包括嗜异性抗体，我们建议对血清标本进行p53蛋白分析的结果应谨慎解读。
